Manufacture of artificial materials



Patented May 23, 1939 UNITED STATES V 2,159,091 menswear; or ARTIFICIAL MATERIALS Robert Wighton Moncrlei! and Frank Brentnall Hill, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application May 5, 1937, Serial No.

Claims.

, his invention relates to improvements in the ..lanufactu re of artificial materials, and particularly to processes for improving the extensibility of filaments, yarns, foils, and similar mates rials having a basis of organic derivatives of cellulose.

It hasbeen discovered that the extensibility of artificial filaments, yarns, foils, and similar materials having a basis of organic derivatives of II cellulose may be increased by treating them with hot aqueous media at a temperature above 100 C. in the absence of tension sufficient to stretch them. The materials which appear to be most susceptible to the treatment are the ordinary dry spun yarns, which usually have an extensibility of about 25%, and by treatment according to the process of the present invention this extensibility may be increased very considerably for example up to 50 or 60% or even more. However, no the normal extensibility of dry spun 'yarns is, in general, sufiicient for most purposes, and the most valuable application of the process of the present invention is in connection with stretched yarns, particularly yarns which have been stretched by not more than about 100% of their original length. Stretching to a considerable extent, for example, to 900% of their original length appears to render the materials more resistant to the treatment of the present invention. A very useful increase in extensibility may, however, be imparted to'materials which have been stretched, for example, to 150.0r 180% of their original length by treatment according to the process of the present invention.

Stretched materials treated according to the process of the present invention may have been obtained by stretching in the presence of steam or hot water, and the process is particularly valuable for the treatment of such materials. Thus they may have been stretched by the processes described in U. S. applications S. Nos.

123,104, 123,105, 123,106 filed January 30, 1937, 121,150, 121,151 and 121,152 filed January 18, 1937, or by a process of simultaneous stretching and lowtwisting as described in U. S. applicationS. No. 111,596 filed November 19, 1936. Materials which have been stretched by other processes, e. g. in the presence of organic swelling agents may, however, also be treated according to the process of the present invention.

The hot aqueous media employed in the process of the present invention may be hot water, steam, preferably wet steam, and dilute aqueous solutions of swelling agents, for example dilute aqueous solutions containing about .1-3 or 5% In Great Britain May 22, 1936 of acetone, methylene ethylene ether, dioxane, or other neutral swelling agent. ,Steam containing small proportions of swelling agents, e. g. '2, 5 or may also be employed. The media may be employed under pressure attemperatures of for 5 example 110 0., 120 0., up to 140 C. or more. Steam, if employed, is preferablyof a fairly high degree of-wetness, e. g. 5 to 10%.

' The time of treatment may vary from a short period of e. g. 1-2 seconds or less up to 10-30 seconds or even to 30 minutes or more according to the nature of the materials treated, the treating medium and the increase in extensibility required. While it is usually desirable that a certain amount of shrinkage shall take place it 6 has been found that a considerable increase in extensibility may be obtained with only a relatively small degree of shrinkage, for example shrinkage of only 2 to 5%.

By the process of the present invention an improved extensibility may be obtained under conditions which vary considerably. For example ordinary dry spun yarn may be treated in wet steam at a temperature of 110, 115 or 130 C. or more for 15 to 30 minutes, or yarn which has been stretched in the presence of. steam or hot water by 30, 50 or 80% of its original length may be treated in water at a temperature of 105- 110 C. or more for 5 to 10 seconds.

The process of the present invention may be carried out duringthe travel of the materials from one point to another, and this method is particularly valuable when employed in conjunction with a stretching operation in steam or hot water such as is described in the specifications referred to above. For example, cellulose acetate yarns may be stretched to 150-200% of their original length in the presence of saturated or wet steam as described in U? S. applications S. Nos. 123,104, 123,105 and 123,106 filed January 30, 1937, and after passing round the stretching rollers 5 illustrated in Figure 1 of the drawings in U. S. applications S. Nos. 123,104, 123,105 and 123,106 filed January 30, 1937, they maypass through avessel containing wet steam or hot water which is under pressure and which may be at the same temperature as the steam employed for stretching, and then pass round another pair of rollers driven at the same rate as rollers 5 or, preferably, at a slightly lower rate, so that the materials are free to shrink between the two sets of rollers. The materials may then be dried and collected on a suitable take up device, for example a creel of bobbins as illustrated at 6 in Figure 1 of the above specificaterials and exerts a tension on the materials which may prevent shrinkageor the full degree of shrinkage, it isv desirable to enclose the rollers before and after the vessel containing the aqueous medium in end chambers containing a fluid 'under pressure and communicating with the vessel through orifices for the passage of the materials as described in U. S. application S. No. 17,242 filed April 19, 1935. By this means tension on the materials during their passage through the shrinking vessel due toflow of fluid mediurn'may be eliminated.

Instead of carrying out the treatment on running materials they may be treated in package form, for example in the form of hanks or on bobbins, which are preferably slackly wound and havea quick traverse. Collapsible or compressible bobbins such that shrinkage is not prevented'may be employed. Preferably bobbins are so designed that the treatment liquid can be circulated through the materials from the inside to the outside of the bobbins and back again alternately.

The following examples illustrate the invention, but are not to be regarded as limiting it:

Example 1 Cellulose acetate yarn which has been stretchedto about 135% of its original length in wet steam is treated with water at about C. for 5 to 10' seconds and is then dried.

Example 2 Cellulose acetate yarn which has been stretched to about 180% of its original length in wet steam is subjected to a hot water treatment similar to that described in Example 1.

Example 3 Ordinary dry spun cellulose acetate yarn is treated with wet steam at a temperature of about 135 C. for 15 to 30 minutes and is then dried.

In each case the extensibility of the yarn is improved. The materials treated according to the process of the present invention may be subjected to further treatments, either continuously with the hot aqueous treatments or as aseparate operation. Such treatment may, for example, be a saponificatlon treatment as described above or a further esterification process such as is described in U. S. applications S. Nos. 39,290, 39,289 and 39,288 filed September 5, 1935.

Having described; our invention what we desire to secure by Letters Patent is:

1. Process iorimproving the extensibility of artificial materials, which comprises subjecting ordinary dry spun filaments, yarns and similar materials of organic derivatives of cellulose, or filaments, yarns and similar materials or organic 'deri'vativesof cellulose which have been stretched to not more than 200% of their original length, to the action of an aqueous medium at a temperature above 100 C. in the absence of tension suificient to stretch them.

2. Process for improving the extensibility of artificial. materials, which comprises subjecting artificial filaments, yarns, foils and similar materials of organic derivatives of cellulose which have been stretched subsequent to their production to not more than 200% of their original length to the action of hot water at a temperature above 100 C. in the absence of tension sufficient to stretch them.

3. Process for improving the extensibility of artificial materials, which comprises subjecting artificial filaments, yarns, foils and similar materials of organic derivatives of cellulose which have been stretched subsequent to their production to not more than 200% of their original length to the action of wet steam at a temperature above 100 C. in the absence of tensionsuificient to stretch them.

4. Process for improving the extensibility of artificial materials, which comprises subjecting artificial filaments, yarns, foils and similar ma-' terials of cellulose acetate which have been stretched subsequent to their production to not more than 200% of their original length tothe action of hot water at a temperature above C in the absence of tension sufli'cient to stretch them.

5. Process for improving theextensibility of artificial materials, which comprises subjecting artificial filaments, yarns, foils and similar materials of cellulose acetate which have been stretched subsequent to their production to not more than 200% of their original length to theaction of wet steam at a temperature above 110 C. in the absence of tension suflicient to stretch ROBERT WIGHTON MONCRIEFF. FRANK BRENTNAIL HILL. 

